Uranus

Uranus, the seventh planet from the sun. Uranus was the first planet to be discovered with a telescope, Mercury, Venus, Mars, Jupiter, and Saturn being readily visible to the unaided eye. Uranus was the first planet to be discovered since ancient times. When Sir William Herschel sighted Uranus in 1781, he at first mistook it for a comet. Under good viewing conditions, it is just visible to a person of keen eyesight. German astronomer Johann E. Bode named Uranus after a sky god in Greek mythology. Uranus and Neptune are similar in size and appearance. In the late 1970s, astronomers discovered that Uranus was encircled by a series of nine narrow rings. Unlike the rings of Saturn, these rings are dark and are probably composed of particles of rock.